You could use any button to do this job. You just need to declare button and handle its OnClick event. In its body you should use FireCommandEvent method of RadTreeList and execute Rebind command. Note that this method is accessible only through specific item from the treelist. So if there are no items in RadTreeList this approach won't work.
I am sending you an example project which is demonstrating the aforementioned approach. Let me know if I can assist you any further.
Regards,
Andrey
the Telerik team
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